/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package misc

import (
	"io"
	"regexp"
	"sync"
)

import (
	"github.com/pkg/errors"
)

var (
	_regexpTable     *regexp.Regexp
	_regexpTableOnce sync.Once
)

func getTableRegexp() *regexp.Regexp {
	_regexpTableOnce.Do(func() {
		_regexpTable = regexp.MustCompile(`([a-zA-Z0-9_-]+)\.([a-zA-Z0-9_-]+)`)
	})
	return _regexpTable
}

func ParseTable(input string) (db, tbl string, err error) {
	mat := getTableRegexp().FindStringSubmatch(input)
	if len(mat) < 1 {
		err = errors.Errorf("invalid table name: %s", input)
		return
	}
	db = mat[1]
	tbl = mat[2]
	return
}

func TryClose(i interface{}) error {
	if c, ok := i.(io.Closer); ok {
		return c.Close()
	}
	return nil
}
